Display devices, utilizing polarized light to create and display animation are generally known and have been used to form animated images on bill-boards, display signs, store windows and the like. Generally, such devices create an image by directing polarized light in a path from a polarized light source to an image screen which contains material having different dirrections of polarization and/or a patterned light intercepting plastic sheet with polarized layer or the like, arranged to selectively pass light therethrough and form an intended image on the screen. The screen, generally comprises transparent or diffusing surfaces and typical prior art polarizing arrangements utilized for forming images are generally disclosed in U.S. Pat. Nos. 2,700,919; 2,977,845; 3,054,204; 3,437,401 and 3,538,322.
Prior art devices utilizing such typical polarizing imaging means have major disadvantages, particularly in achieving uniform illumination of the viewing screen. Generally, such devices require significant spacing between the light source and the screen, or incorporation of high density diffusors between the light source and the screen to enable uniform illumination of a screen area of significant dimension. The large space requirement and/or use of high density diffusers, generally requires significant increases in light source brightness of the system which generally results in higher energy consumption and heat generation problems which in turn generally require elaborate provision for the dissipation of heat at the light source.
U.S. Pat. No. 3,676,845 to Siksai discloses an interesting automotive turn signal indicating system wherein a generally cylindrical beam of polarized light is directed to an elongated rectilinear mirror, arranged within the beam of polarized light at an angle to the axis of the polarized light beam. The mirror has a plurality of parallel light reflecting ridges arranged generally perpendicular to the axis of the polarized light beam and polarized light, which engages the elongated rectilinear mirror, is reflected by the parallel ridges of the mirror to illuminate a viewing screen having the general rectilinear shape of the mirror. A rotating polarizing screen, in the path of the light source, provides polarized light incrementally along the length of the elongated mirror which is reflected to the viewing screen and forms an image of an arrow moving across the screen in the direction of intended turning.
An object of the present invention is to provide a animated polarized light display device that is a compact arrangement and can provide uniform illumination to an enlarged viewing screen.
Another object of the present invention is to provide an animated polarized light display device which can furnish a uniformly bright image, to an enlarged viewing screen, with a light source of modest intensity.
A still further object of the invention is to provide a compact arrangement for transforming a polarized light beam to a enlarged cross-sectional size, while maintaining generally uniform and bright viewing screen illumination.
These and other objects of the invention will become apparent from the following description of the embodiments.